1. Field of the Invention
This invention relates to a power tool and, more particularly, to a pneumatically-operated tool, such as a scraping tool for removing moldings, emblems and the like.
2. Description of the Prior Art
The present invention is an improvement of the scraping tool disclosed in U.S. Pat. No. 4,416,338. That patent discloses a pneumatically operated hammer assembly of the reciprocating piston type. The tool has a cylindrical housing which receives in the forward or working end thereof one end of an anvil or blade holder, which is fixed to the cylindrical housing, as by roll pins. The outer end of the blade holder is, in turn, fixed to a scraping blade. A pneumatic control assembly is coupled to the rear end of the cylindrical housing and a piston slidably reciprocates inside the housing between this control assembly and the anvil or blade holder. The control assembly includes a ball valve which responds to pressure differences to automatically alternate between positions respectively admitting pressurized air ahead of or behind the piston to control its reciprocation. Each time the piston moves forwardly it impacts the anvil to impart a vibrational force to the scraping blade.
This prior scraping tool is designed for removing stuck gasket material from automotive engine parts. While the tool performs adequately for that purpose, it has relatively low output and is unable to cut through molding adhesive. Because the blade holder is pinned to the housing, the blade simply vibrates and does no work.
In the prior scraping tool, the blade is affixed to the blade holder by means of a set screw which extends through an opening in the blade. The blade can be damaged in use and/or may need sharpening. Also, it is desirable to offer blades in different sizes, all of which will require removal of the blade from the holder. This is somewhat cumbersome and time consuming in the prior art device, requiring the use of a screwdriver or similar tool. In the prior scraping tool, since the anvil or blade holder is pinned to the housing, is cannot be removed.